I've got a process that creates pdfs from html and then merges them into one pdf. If I just look at one of the generated pdfs before merge it looks fine, but after the merge of pdfs, the pages seem to be stretched vertically. Is there a setting I am missing somewhere?

PdfDocument mergeDoc = PdfDocument.Merge(pdfs.ToArray());
MemoryStream pdfMemoryStream = new MemoryStream();
mergeDoc.Save(pdfMemoryStream);